linux-stable/fs/fuse/inode.c
Miklos Szeredi 5d069dbe8a fuse: fix bad inode
Jan Kara's analysis of the syzbot report (edited):

  The reproducer opens a directory on FUSE filesystem, it then attaches
  dnotify mark to the open directory.  After that a fuse_do_getattr() call
  finds that attributes returned by the server are inconsistent, and calls
  make_bad_inode() which, among other things does:

          inode->i_mode = S_IFREG;

  This then confuses dnotify which doesn't tear down its structures
  properly and eventually crashes.

Avoid calling make_bad_inode() on a live inode: switch to a private flag on
the fuse inode.  Also add the test to ops which the bad_inode_ops would
have caught.

This bug goes back to the initial merge of fuse in 2.6.14...

Reported-by: syzbot+f427adf9324b92652ccc@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>
2020-12-10 15:33:14 +01:00

1754 lines
41 KiB
C

/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
#include "fuse_i.h"
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/statfs.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/exportfs.h>
#include <linux/posix_acl.h>
#include <linux/pid_namespace.h>
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Filesystem in Userspace");
MODULE_LICENSE("GPL");
static struct kmem_cache *fuse_inode_cachep;
struct list_head fuse_conn_list;
DEFINE_MUTEX(fuse_mutex);
static int set_global_limit(const char *val, const struct kernel_param *kp);
unsigned max_user_bgreq;
module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
&max_user_bgreq, 0644);
__MODULE_PARM_TYPE(max_user_bgreq, "uint");
MODULE_PARM_DESC(max_user_bgreq,
"Global limit for the maximum number of backgrounded requests an "
"unprivileged user can set");
unsigned max_user_congthresh;
module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
&max_user_congthresh, 0644);
__MODULE_PARM_TYPE(max_user_congthresh, "uint");
MODULE_PARM_DESC(max_user_congthresh,
"Global limit for the maximum congestion threshold an "
"unprivileged user can set");
#define FUSE_SUPER_MAGIC 0x65735546
#define FUSE_DEFAULT_BLKSIZE 512
/** Maximum number of outstanding background requests */
#define FUSE_DEFAULT_MAX_BACKGROUND 12
/** Congestion starts at 75% of maximum */
#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
#ifdef CONFIG_BLOCK
static struct file_system_type fuseblk_fs_type;
#endif
struct fuse_forget_link *fuse_alloc_forget(void)
{
return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
}
static struct inode *fuse_alloc_inode(struct super_block *sb)
{
struct fuse_inode *fi;
fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
if (!fi)
return NULL;
fi->i_time = 0;
fi->inval_mask = 0;
fi->nodeid = 0;
fi->nlookup = 0;
fi->attr_version = 0;
fi->orig_ino = 0;
fi->state = 0;
mutex_init(&fi->mutex);
init_rwsem(&fi->i_mmap_sem);
spin_lock_init(&fi->lock);
fi->forget = fuse_alloc_forget();
if (!fi->forget)
goto out_free;
if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
goto out_free_forget;
return &fi->inode;
out_free_forget:
kfree(fi->forget);
out_free:
kmem_cache_free(fuse_inode_cachep, fi);
return NULL;
}
static void fuse_free_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
mutex_destroy(&fi->mutex);
kfree(fi->forget);
#ifdef CONFIG_FUSE_DAX
kfree(fi->dax);
#endif
kmem_cache_free(fuse_inode_cachep, fi);
}
static void fuse_evict_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (inode->i_sb->s_flags & SB_ACTIVE) {
struct fuse_conn *fc = get_fuse_conn(inode);
if (FUSE_IS_DAX(inode))
fuse_dax_inode_cleanup(inode);
if (fi->nlookup) {
fuse_queue_forget(fc, fi->forget, fi->nodeid,
fi->nlookup);
fi->forget = NULL;
}
}
if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
WARN_ON(!list_empty(&fi->write_files));
WARN_ON(!list_empty(&fi->queued_writes));
}
}
static int fuse_reconfigure(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
sync_filesystem(sb);
if (fc->sb_flags & SB_MANDLOCK)
return -EINVAL;
return 0;
}
/*
* ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
* so that it will fit.
*/
static ino_t fuse_squash_ino(u64 ino64)
{
ino_t ino = (ino_t) ino64;
if (sizeof(ino_t) < sizeof(u64))
ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
return ino;
}
void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
u64 attr_valid)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
lockdep_assert_held(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
fi->i_time = attr_valid;
WRITE_ONCE(fi->inval_mask, 0);
inode->i_ino = fuse_squash_ino(attr->ino);
inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
set_nlink(inode, attr->nlink);
inode->i_uid = make_kuid(fc->user_ns, attr->uid);
inode->i_gid = make_kgid(fc->user_ns, attr->gid);
inode->i_blocks = attr->blocks;
inode->i_atime.tv_sec = attr->atime;
inode->i_atime.tv_nsec = attr->atimensec;
/* mtime from server may be stale due to local buffered write */
if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
inode->i_mtime.tv_sec = attr->mtime;
inode->i_mtime.tv_nsec = attr->mtimensec;
inode->i_ctime.tv_sec = attr->ctime;
inode->i_ctime.tv_nsec = attr->ctimensec;
}
if (attr->blksize != 0)
inode->i_blkbits = ilog2(attr->blksize);
else
inode->i_blkbits = inode->i_sb->s_blocksize_bits;
/*
* Don't set the sticky bit in i_mode, unless we want the VFS
* to check permissions. This prevents failures due to the
* check in may_delete().
*/
fi->orig_i_mode = inode->i_mode;
if (!fc->default_permissions)
inode->i_mode &= ~S_ISVTX;
fi->orig_ino = attr->ino;
/*
* We are refreshing inode data and it is possible that another
* client set suid/sgid or security.capability xattr. So clear
* S_NOSEC. Ideally, we could have cleared it only if suid/sgid
* was set or if security.capability xattr was set. But we don't
* know if security.capability has been set or not. So clear it
* anyway. Its less efficient but should be safe.
*/
inode->i_flags &= ~S_NOSEC;
}
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
bool is_wb = fc->writeback_cache;
loff_t oldsize;
struct timespec64 old_mtime;
spin_lock(&fi->lock);
if ((attr_version != 0 && fi->attr_version > attr_version) ||
test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
spin_unlock(&fi->lock);
return;
}
old_mtime = inode->i_mtime;
fuse_change_attributes_common(inode, attr, attr_valid);
oldsize = inode->i_size;
/*
* In case of writeback_cache enabled, the cached writes beyond EOF
* extend local i_size without keeping userspace server in sync. So,
* attr->size coming from server can be stale. We cannot trust it.
*/
if (!is_wb || !S_ISREG(inode->i_mode))
i_size_write(inode, attr->size);
spin_unlock(&fi->lock);
if (!is_wb && S_ISREG(inode->i_mode)) {
bool inval = false;
if (oldsize != attr->size) {
truncate_pagecache(inode, attr->size);
if (!fc->explicit_inval_data)
inval = true;
} else if (fc->auto_inval_data) {
struct timespec64 new_mtime = {
.tv_sec = attr->mtime,
.tv_nsec = attr->mtimensec,
};
/*
* Auto inval mode also checks and invalidates if mtime
* has changed.
*/
if (!timespec64_equal(&old_mtime, &new_mtime))
inval = true;
}
if (inval)
invalidate_inode_pages2(inode->i_mapping);
}
}
static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
{
inode->i_mode = attr->mode & S_IFMT;
inode->i_size = attr->size;
inode->i_mtime.tv_sec = attr->mtime;
inode->i_mtime.tv_nsec = attr->mtimensec;
inode->i_ctime.tv_sec = attr->ctime;
inode->i_ctime.tv_nsec = attr->ctimensec;
if (S_ISREG(inode->i_mode)) {
fuse_init_common(inode);
fuse_init_file_inode(inode);
} else if (S_ISDIR(inode->i_mode))
fuse_init_dir(inode);
else if (S_ISLNK(inode->i_mode))
fuse_init_symlink(inode);
else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
fuse_init_common(inode);
init_special_inode(inode, inode->i_mode,
new_decode_dev(attr->rdev));
} else
BUG();
}
static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
{
u64 nodeid = *(u64 *) _nodeidp;
if (get_node_id(inode) == nodeid)
return 1;
else
return 0;
}
static int fuse_inode_set(struct inode *inode, void *_nodeidp)
{
u64 nodeid = *(u64 *) _nodeidp;
get_fuse_inode(inode)->nodeid = nodeid;
return 0;
}
struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
int generation, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version)
{
struct inode *inode;
struct fuse_inode *fi;
struct fuse_conn *fc = get_fuse_conn_super(sb);
/*
* Auto mount points get their node id from the submount root, which is
* not a unique identifier within this filesystem.
*
* To avoid conflicts, do not place submount points into the inode hash
* table.
*/
if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
S_ISDIR(attr->mode)) {
inode = new_inode(sb);
if (!inode)
return NULL;
fuse_init_inode(inode, attr);
get_fuse_inode(inode)->nodeid = nodeid;
inode->i_flags |= S_AUTOMOUNT;
goto done;
}
retry:
inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
if (!inode)
return NULL;
if ((inode->i_state & I_NEW)) {
inode->i_flags |= S_NOATIME;
if (!fc->writeback_cache || !S_ISREG(attr->mode))
inode->i_flags |= S_NOCMTIME;
inode->i_generation = generation;
fuse_init_inode(inode, attr);
unlock_new_inode(inode);
} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
/* Inode has changed type, any I/O on the old should fail */
fuse_make_bad(inode);
iput(inode);
goto retry;
}
done:
fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->nlookup++;
spin_unlock(&fi->lock);
fuse_change_attributes(inode, attr, attr_valid, attr_version);
return inode;
}
struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
struct fuse_mount **fm)
{
struct fuse_mount *fm_iter;
struct inode *inode;
WARN_ON(!rwsem_is_locked(&fc->killsb));
list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
if (!fm_iter->sb)
continue;
inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
if (inode) {
if (fm)
*fm = fm_iter;
return inode;
}
}
return NULL;
}
int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
loff_t offset, loff_t len)
{
struct fuse_inode *fi;
struct inode *inode;
pgoff_t pg_start;
pgoff_t pg_end;
inode = fuse_ilookup(fc, nodeid, NULL);
if (!inode)
return -ENOENT;
fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
spin_unlock(&fi->lock);
fuse_invalidate_attr(inode);
forget_all_cached_acls(inode);
if (offset >= 0) {
pg_start = offset >> PAGE_SHIFT;
if (len <= 0)
pg_end = -1;
else
pg_end = (offset + len - 1) >> PAGE_SHIFT;
invalidate_inode_pages2_range(inode->i_mapping,
pg_start, pg_end);
}
iput(inode);
return 0;
}
bool fuse_lock_inode(struct inode *inode)
{
bool locked = false;
if (!get_fuse_conn(inode)->parallel_dirops) {
mutex_lock(&get_fuse_inode(inode)->mutex);
locked = true;
}
return locked;
}
void fuse_unlock_inode(struct inode *inode, bool locked)
{
if (locked)
mutex_unlock(&get_fuse_inode(inode)->mutex);
}
static void fuse_umount_begin(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
if (!fc->no_force_umount)
fuse_abort_conn(fc);
}
static void fuse_send_destroy(struct fuse_mount *fm)
{
if (fm->fc->conn_init) {
FUSE_ARGS(args);
args.opcode = FUSE_DESTROY;
args.force = true;
args.nocreds = true;
fuse_simple_request(fm, &args);
}
}
static void fuse_put_super(struct super_block *sb)
{
struct fuse_mount *fm = get_fuse_mount_super(sb);
fuse_conn_put(fm->fc);
kfree(fm);
}
static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
{
stbuf->f_type = FUSE_SUPER_MAGIC;
stbuf->f_bsize = attr->bsize;
stbuf->f_frsize = attr->frsize;
stbuf->f_blocks = attr->blocks;
stbuf->f_bfree = attr->bfree;
stbuf->f_bavail = attr->bavail;
stbuf->f_files = attr->files;
stbuf->f_ffree = attr->ffree;
stbuf->f_namelen = attr->namelen;
/* fsid is left zero */
}
static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct fuse_mount *fm = get_fuse_mount_super(sb);
FUSE_ARGS(args);
struct fuse_statfs_out outarg;
int err;
if (!fuse_allow_current_process(fm->fc)) {
buf->f_type = FUSE_SUPER_MAGIC;
return 0;
}
memset(&outarg, 0, sizeof(outarg));
args.in_numargs = 0;
args.opcode = FUSE_STATFS;
args.nodeid = get_node_id(d_inode(dentry));
args.out_numargs = 1;
args.out_args[0].size = sizeof(outarg);
args.out_args[0].value = &outarg;
err = fuse_simple_request(fm, &args);
if (!err)
convert_fuse_statfs(buf, &outarg.st);
return err;
}
enum {
OPT_SOURCE,
OPT_SUBTYPE,
OPT_FD,
OPT_ROOTMODE,
OPT_USER_ID,
OPT_GROUP_ID,
OPT_DEFAULT_PERMISSIONS,
OPT_ALLOW_OTHER,
OPT_MAX_READ,
OPT_BLKSIZE,
OPT_ERR
};
static const struct fs_parameter_spec fuse_fs_parameters[] = {
fsparam_string ("source", OPT_SOURCE),
fsparam_u32 ("fd", OPT_FD),
fsparam_u32oct ("rootmode", OPT_ROOTMODE),
fsparam_u32 ("user_id", OPT_USER_ID),
fsparam_u32 ("group_id", OPT_GROUP_ID),
fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
fsparam_u32 ("max_read", OPT_MAX_READ),
fsparam_u32 ("blksize", OPT_BLKSIZE),
fsparam_string ("subtype", OPT_SUBTYPE),
{}
};
static int fuse_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct fs_parse_result result;
struct fuse_fs_context *ctx = fc->fs_private;
int opt;
if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
/*
* Ignore options coming from mount(MS_REMOUNT) for backward
* compatibility.
*/
if (fc->oldapi)
return 0;
return invalfc(fc, "No changes allowed in reconfigure");
}
opt = fs_parse(fc, fuse_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case OPT_SOURCE:
if (fc->source)
return invalfc(fc, "Multiple sources specified");
fc->source = param->string;
param->string = NULL;
break;
case OPT_SUBTYPE:
if (ctx->subtype)
return invalfc(fc, "Multiple subtypes specified");
ctx->subtype = param->string;
param->string = NULL;
return 0;
case OPT_FD:
ctx->fd = result.uint_32;
ctx->fd_present = true;
break;
case OPT_ROOTMODE:
if (!fuse_valid_type(result.uint_32))
return invalfc(fc, "Invalid rootmode");
ctx->rootmode = result.uint_32;
ctx->rootmode_present = true;
break;
case OPT_USER_ID:
ctx->user_id = make_kuid(fc->user_ns, result.uint_32);
if (!uid_valid(ctx->user_id))
return invalfc(fc, "Invalid user_id");
ctx->user_id_present = true;
break;
case OPT_GROUP_ID:
ctx->group_id = make_kgid(fc->user_ns, result.uint_32);
if (!gid_valid(ctx->group_id))
return invalfc(fc, "Invalid group_id");
ctx->group_id_present = true;
break;
case OPT_DEFAULT_PERMISSIONS:
ctx->default_permissions = true;
break;
case OPT_ALLOW_OTHER:
ctx->allow_other = true;
break;
case OPT_MAX_READ:
ctx->max_read = result.uint_32;
break;
case OPT_BLKSIZE:
if (!ctx->is_bdev)
return invalfc(fc, "blksize only supported for fuseblk");
ctx->blksize = result.uint_32;
break;
default:
return -EINVAL;
}
return 0;
}
static void fuse_free_fc(struct fs_context *fc)
{
struct fuse_fs_context *ctx = fc->fs_private;
if (ctx) {
kfree(ctx->subtype);
kfree(ctx);
}
}
static int fuse_show_options(struct seq_file *m, struct dentry *root)
{
struct super_block *sb = root->d_sb;
struct fuse_conn *fc = get_fuse_conn_super(sb);
if (fc->legacy_opts_show) {
seq_printf(m, ",user_id=%u",
from_kuid_munged(fc->user_ns, fc->user_id));
seq_printf(m, ",group_id=%u",
from_kgid_munged(fc->user_ns, fc->group_id));
if (fc->default_permissions)
seq_puts(m, ",default_permissions");
if (fc->allow_other)
seq_puts(m, ",allow_other");
if (fc->max_read != ~0)
seq_printf(m, ",max_read=%u", fc->max_read);
if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
seq_printf(m, ",blksize=%lu", sb->s_blocksize);
}
#ifdef CONFIG_FUSE_DAX
if (fc->dax)
seq_puts(m, ",dax");
#endif
return 0;
}
static void fuse_iqueue_init(struct fuse_iqueue *fiq,
const struct fuse_iqueue_ops *ops,
void *priv)
{
memset(fiq, 0, sizeof(struct fuse_iqueue));
spin_lock_init(&fiq->lock);
init_waitqueue_head(&fiq->waitq);
INIT_LIST_HEAD(&fiq->pending);
INIT_LIST_HEAD(&fiq->interrupts);
fiq->forget_list_tail = &fiq->forget_list_head;
fiq->connected = 1;
fiq->ops = ops;
fiq->priv = priv;
}
static void fuse_pqueue_init(struct fuse_pqueue *fpq)
{
unsigned int i;
spin_lock_init(&fpq->lock);
for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
INIT_LIST_HEAD(&fpq->processing[i]);
INIT_LIST_HEAD(&fpq->io);
fpq->connected = 1;
}
void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
struct user_namespace *user_ns,
const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
{
memset(fc, 0, sizeof(*fc));
spin_lock_init(&fc->lock);
spin_lock_init(&fc->bg_lock);
init_rwsem(&fc->killsb);
refcount_set(&fc->count, 1);
atomic_set(&fc->dev_count, 1);
init_waitqueue_head(&fc->blocked_waitq);
fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
INIT_LIST_HEAD(&fc->bg_queue);
INIT_LIST_HEAD(&fc->entry);
INIT_LIST_HEAD(&fc->devices);
atomic_set(&fc->num_waiting, 0);
fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
atomic64_set(&fc->khctr, 0);
fc->polled_files = RB_ROOT;
fc->blocked = 0;
fc->initialized = 0;
fc->connected = 1;
atomic64_set(&fc->attr_version, 1);
get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
fc->user_ns = get_user_ns(user_ns);
fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
INIT_LIST_HEAD(&fc->mounts);
list_add(&fm->fc_entry, &fc->mounts);
fm->fc = fc;
}
EXPORT_SYMBOL_GPL(fuse_conn_init);
void fuse_conn_put(struct fuse_conn *fc)
{
if (refcount_dec_and_test(&fc->count)) {
struct fuse_iqueue *fiq = &fc->iq;
if (IS_ENABLED(CONFIG_FUSE_DAX))
fuse_dax_conn_free(fc);
if (fiq->ops->release)
fiq->ops->release(fiq);
put_pid_ns(fc->pid_ns);
put_user_ns(fc->user_ns);
fc->release(fc);
}
}
EXPORT_SYMBOL_GPL(fuse_conn_put);
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
{
refcount_inc(&fc->count);
return fc;
}
EXPORT_SYMBOL_GPL(fuse_conn_get);
static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
{
struct fuse_attr attr;
memset(&attr, 0, sizeof(attr));
attr.mode = mode;
attr.ino = FUSE_ROOT_ID;
attr.nlink = 1;
return fuse_iget(sb, 1, 0, &attr, 0, 0);
}
struct fuse_inode_handle {
u64 nodeid;
u32 generation;
};
static struct dentry *fuse_get_dentry(struct super_block *sb,
struct fuse_inode_handle *handle)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
struct inode *inode;
struct dentry *entry;
int err = -ESTALE;
if (handle->nodeid == 0)
goto out_err;
inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
if (!inode) {
struct fuse_entry_out outarg;
const struct qstr name = QSTR_INIT(".", 1);
if (!fc->export_support)
goto out_err;
err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
&inode);
if (err && err != -ENOENT)
goto out_err;
if (err || !inode) {
err = -ESTALE;
goto out_err;
}
err = -EIO;
if (get_node_id(inode) != handle->nodeid)
goto out_iput;
}
err = -ESTALE;
if (inode->i_generation != handle->generation)
goto out_iput;
entry = d_obtain_alias(inode);
if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
fuse_invalidate_entry_cache(entry);
return entry;
out_iput:
iput(inode);
out_err:
return ERR_PTR(err);
}
static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
struct inode *parent)
{
int len = parent ? 6 : 3;
u64 nodeid;
u32 generation;
if (*max_len < len) {
*max_len = len;
return FILEID_INVALID;
}
nodeid = get_fuse_inode(inode)->nodeid;
generation = inode->i_generation;
fh[0] = (u32)(nodeid >> 32);
fh[1] = (u32)(nodeid & 0xffffffff);
fh[2] = generation;
if (parent) {
nodeid = get_fuse_inode(parent)->nodeid;
generation = parent->i_generation;
fh[3] = (u32)(nodeid >> 32);
fh[4] = (u32)(nodeid & 0xffffffff);
fh[5] = generation;
}
*max_len = len;
return parent ? 0x82 : 0x81;
}
static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
struct fuse_inode_handle handle;
if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
return NULL;
handle.nodeid = (u64) fid->raw[0] << 32;
handle.nodeid |= (u64) fid->raw[1];
handle.generation = fid->raw[2];
return fuse_get_dentry(sb, &handle);
}
static struct dentry *fuse_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
struct fuse_inode_handle parent;
if (fh_type != 0x82 || fh_len < 6)
return NULL;
parent.nodeid = (u64) fid->raw[3] << 32;
parent.nodeid |= (u64) fid->raw[4];
parent.generation = fid->raw[5];
return fuse_get_dentry(sb, &parent);
}
static struct dentry *fuse_get_parent(struct dentry *child)
{
struct inode *child_inode = d_inode(child);
struct fuse_conn *fc = get_fuse_conn(child_inode);
struct inode *inode;
struct dentry *parent;
struct fuse_entry_out outarg;
const struct qstr name = QSTR_INIT("..", 2);
int err;
if (!fc->export_support)
return ERR_PTR(-ESTALE);
err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
&name, &outarg, &inode);
if (err) {
if (err == -ENOENT)
return ERR_PTR(-ESTALE);
return ERR_PTR(err);
}
parent = d_obtain_alias(inode);
if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
fuse_invalidate_entry_cache(parent);
return parent;
}
static const struct export_operations fuse_export_operations = {
.fh_to_dentry = fuse_fh_to_dentry,
.fh_to_parent = fuse_fh_to_parent,
.encode_fh = fuse_encode_fh,
.get_parent = fuse_get_parent,
};
static const struct super_operations fuse_super_operations = {
.alloc_inode = fuse_alloc_inode,
.free_inode = fuse_free_inode,
.evict_inode = fuse_evict_inode,
.write_inode = fuse_write_inode,
.drop_inode = generic_delete_inode,
.put_super = fuse_put_super,
.umount_begin = fuse_umount_begin,
.statfs = fuse_statfs,
.show_options = fuse_show_options,
};
static void sanitize_global_limit(unsigned *limit)
{
/*
* The default maximum number of async requests is calculated to consume
* 1/2^13 of the total memory, assuming 392 bytes per request.
*/
if (*limit == 0)
*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
if (*limit >= 1 << 16)
*limit = (1 << 16) - 1;
}
static int set_global_limit(const char *val, const struct kernel_param *kp)
{
int rv;
rv = param_set_uint(val, kp);
if (rv)
return rv;
sanitize_global_limit((unsigned *)kp->arg);
return 0;
}
static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
{
int cap_sys_admin = capable(CAP_SYS_ADMIN);
if (arg->minor < 13)
return;
sanitize_global_limit(&max_user_bgreq);
sanitize_global_limit(&max_user_congthresh);
spin_lock(&fc->bg_lock);
if (arg->max_background) {
fc->max_background = arg->max_background;
if (!cap_sys_admin && fc->max_background > max_user_bgreq)
fc->max_background = max_user_bgreq;
}
if (arg->congestion_threshold) {
fc->congestion_threshold = arg->congestion_threshold;
if (!cap_sys_admin &&
fc->congestion_threshold > max_user_congthresh)
fc->congestion_threshold = max_user_congthresh;
}
spin_unlock(&fc->bg_lock);
}
struct fuse_init_args {
struct fuse_args args;
struct fuse_init_in in;
struct fuse_init_out out;
};
static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
int error)
{
struct fuse_conn *fc = fm->fc;
struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
struct fuse_init_out *arg = &ia->out;
bool ok = true;
if (error || arg->major != FUSE_KERNEL_VERSION)
ok = false;
else {
unsigned long ra_pages;
process_init_limits(fc, arg);
if (arg->minor >= 6) {
ra_pages = arg->max_readahead / PAGE_SIZE;
if (arg->flags & FUSE_ASYNC_READ)
fc->async_read = 1;
if (!(arg->flags & FUSE_POSIX_LOCKS))
fc->no_lock = 1;
if (arg->minor >= 17) {
if (!(arg->flags & FUSE_FLOCK_LOCKS))
fc->no_flock = 1;
} else {
if (!(arg->flags & FUSE_POSIX_LOCKS))
fc->no_flock = 1;
}
if (arg->flags & FUSE_ATOMIC_O_TRUNC)
fc->atomic_o_trunc = 1;
if (arg->minor >= 9) {
/* LOOKUP has dependency on proto version */
if (arg->flags & FUSE_EXPORT_SUPPORT)
fc->export_support = 1;
}
if (arg->flags & FUSE_BIG_WRITES)
fc->big_writes = 1;
if (arg->flags & FUSE_DONT_MASK)
fc->dont_mask = 1;
if (arg->flags & FUSE_AUTO_INVAL_DATA)
fc->auto_inval_data = 1;
else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
fc->explicit_inval_data = 1;
if (arg->flags & FUSE_DO_READDIRPLUS) {
fc->do_readdirplus = 1;
if (arg->flags & FUSE_READDIRPLUS_AUTO)
fc->readdirplus_auto = 1;
}
if (arg->flags & FUSE_ASYNC_DIO)
fc->async_dio = 1;
if (arg->flags & FUSE_WRITEBACK_CACHE)
fc->writeback_cache = 1;
if (arg->flags & FUSE_PARALLEL_DIROPS)
fc->parallel_dirops = 1;
if (arg->flags & FUSE_HANDLE_KILLPRIV)
fc->handle_killpriv = 1;
if (arg->time_gran && arg->time_gran <= 1000000000)
fm->sb->s_time_gran = arg->time_gran;
if ((arg->flags & FUSE_POSIX_ACL)) {
fc->default_permissions = 1;
fc->posix_acl = 1;
fm->sb->s_xattr = fuse_acl_xattr_handlers;
}
if (arg->flags & FUSE_CACHE_SYMLINKS)
fc->cache_symlinks = 1;
if (arg->flags & FUSE_ABORT_ERROR)
fc->abort_err = 1;
if (arg->flags & FUSE_MAX_PAGES) {
fc->max_pages =
min_t(unsigned int, FUSE_MAX_MAX_PAGES,
max_t(unsigned int, arg->max_pages, 1));
}
if (IS_ENABLED(CONFIG_FUSE_DAX) &&
arg->flags & FUSE_MAP_ALIGNMENT &&
!fuse_dax_check_alignment(fc, arg->map_alignment)) {
ok = false;
}
if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) {
fc->handle_killpriv_v2 = 1;
fm->sb->s_flags |= SB_NOSEC;
}
} else {
ra_pages = fc->max_read / PAGE_SIZE;
fc->no_lock = 1;
fc->no_flock = 1;
}
fm->sb->s_bdi->ra_pages =
min(fm->sb->s_bdi->ra_pages, ra_pages);
fc->minor = arg->minor;
fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
fc->max_write = max_t(unsigned, 4096, fc->max_write);
fc->conn_init = 1;
}
kfree(ia);
if (!ok) {
fc->conn_init = 0;
fc->conn_error = 1;
}
fuse_set_initialized(fc);
wake_up_all(&fc->blocked_waitq);
}
void fuse_send_init(struct fuse_mount *fm)
{
struct fuse_init_args *ia;
ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
ia->in.major = FUSE_KERNEL_VERSION;
ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
ia->in.flags |=
FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
FUSE_HANDLE_KILLPRIV_V2;
#ifdef CONFIG_FUSE_DAX
if (fm->fc->dax)
ia->in.flags |= FUSE_MAP_ALIGNMENT;
#endif
if (fm->fc->auto_submounts)
ia->in.flags |= FUSE_SUBMOUNTS;
ia->args.opcode = FUSE_INIT;
ia->args.in_numargs = 1;
ia->args.in_args[0].size = sizeof(ia->in);
ia->args.in_args[0].value = &ia->in;
ia->args.out_numargs = 1;
/* Variable length argument used for backward compatibility
with interface version < 7.5. Rest of init_out is zeroed
by do_get_request(), so a short reply is not a problem */
ia->args.out_argvar = true;
ia->args.out_args[0].size = sizeof(ia->out);
ia->args.out_args[0].value = &ia->out;
ia->args.force = true;
ia->args.nocreds = true;
ia->args.end = process_init_reply;
if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
process_init_reply(fm, &ia->args, -ENOTCONN);
}
EXPORT_SYMBOL_GPL(fuse_send_init);
void fuse_free_conn(struct fuse_conn *fc)
{
WARN_ON(!list_empty(&fc->devices));
kfree_rcu(fc, rcu);
}
EXPORT_SYMBOL_GPL(fuse_free_conn);
static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
{
int err;
char *suffix = "";
if (sb->s_bdev) {
suffix = "-fuseblk";
/*
* sb->s_bdi points to blkdev's bdi however we want to redirect
* it to our private bdi...
*/
bdi_put(sb->s_bdi);
sb->s_bdi = &noop_backing_dev_info;
}
err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
MINOR(fc->dev), suffix);
if (err)
return err;
/* fuse does it's own writeback accounting */
sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
/*
* For a single fuse filesystem use max 1% of dirty +
* writeback threshold.
*
* This gives about 1M of write buffer for memory maps on a
* machine with 1G and 10% dirty_ratio, which should be more
* than enough.
*
* Privileged users can raise it by writing to
*
* /sys/class/bdi/<bdi>/max_ratio
*/
bdi_set_max_ratio(sb->s_bdi, 1);
return 0;
}
struct fuse_dev *fuse_dev_alloc(void)
{
struct fuse_dev *fud;
struct list_head *pq;
fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
if (!fud)
return NULL;
pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
if (!pq) {
kfree(fud);
return NULL;
}
fud->pq.processing = pq;
fuse_pqueue_init(&fud->pq);
return fud;
}
EXPORT_SYMBOL_GPL(fuse_dev_alloc);
void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
{
fud->fc = fuse_conn_get(fc);
spin_lock(&fc->lock);
list_add_tail(&fud->entry, &fc->devices);
spin_unlock(&fc->lock);
}
EXPORT_SYMBOL_GPL(fuse_dev_install);
struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
{
struct fuse_dev *fud;
fud = fuse_dev_alloc();
if (!fud)
return NULL;
fuse_dev_install(fud, fc);
return fud;
}
EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
void fuse_dev_free(struct fuse_dev *fud)
{
struct fuse_conn *fc = fud->fc;
if (fc) {
spin_lock(&fc->lock);
list_del(&fud->entry);
spin_unlock(&fc->lock);
fuse_conn_put(fc);
}
kfree(fud->pq.processing);
kfree(fud);
}
EXPORT_SYMBOL_GPL(fuse_dev_free);
static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
const struct fuse_inode *fi)
{
*attr = (struct fuse_attr){
.ino = fi->inode.i_ino,
.size = fi->inode.i_size,
.blocks = fi->inode.i_blocks,
.atime = fi->inode.i_atime.tv_sec,
.mtime = fi->inode.i_mtime.tv_sec,
.ctime = fi->inode.i_ctime.tv_sec,
.atimensec = fi->inode.i_atime.tv_nsec,
.mtimensec = fi->inode.i_mtime.tv_nsec,
.ctimensec = fi->inode.i_ctime.tv_nsec,
.mode = fi->inode.i_mode,
.nlink = fi->inode.i_nlink,
.uid = fi->inode.i_uid.val,
.gid = fi->inode.i_gid.val,
.rdev = fi->inode.i_rdev,
.blksize = 1u << fi->inode.i_blkbits,
};
}
static void fuse_sb_defaults(struct super_block *sb)
{
sb->s_magic = FUSE_SUPER_MAGIC;
sb->s_op = &fuse_super_operations;
sb->s_xattr = fuse_xattr_handlers;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_time_gran = 1;
sb->s_export_op = &fuse_export_operations;
sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
if (sb->s_user_ns != &init_user_ns)
sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
/*
* If we are not in the initial user namespace posix
* acls must be translated.
*/
if (sb->s_user_ns != &init_user_ns)
sb->s_xattr = fuse_no_acl_xattr_handlers;
}
int fuse_fill_super_submount(struct super_block *sb,
struct fuse_inode *parent_fi)
{
struct fuse_mount *fm = get_fuse_mount_super(sb);
struct super_block *parent_sb = parent_fi->inode.i_sb;
struct fuse_attr root_attr;
struct inode *root;
fuse_sb_defaults(sb);
fm->sb = sb;
WARN_ON(sb->s_bdi != &noop_backing_dev_info);
sb->s_bdi = bdi_get(parent_sb->s_bdi);
sb->s_xattr = parent_sb->s_xattr;
sb->s_time_gran = parent_sb->s_time_gran;
sb->s_blocksize = parent_sb->s_blocksize;
sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
if (parent_sb->s_subtype && !sb->s_subtype)
return -ENOMEM;
fuse_fill_attr_from_inode(&root_attr, parent_fi);
root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
/*
* This inode is just a duplicate, so it is not looked up and
* its nlookup should not be incremented. fuse_iget() does
* that, though, so undo it here.
*/
get_fuse_inode(root)->nlookup--;
sb->s_d_op = &fuse_dentry_operations;
sb->s_root = d_make_root(root);
if (!sb->s_root)
return -ENOMEM;
return 0;
}
int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
{
struct fuse_dev *fud = NULL;
struct fuse_mount *fm = get_fuse_mount_super(sb);
struct fuse_conn *fc = fm->fc;
struct inode *root;
struct dentry *root_dentry;
int err;
err = -EINVAL;
if (sb->s_flags & SB_MANDLOCK)
goto err;
fuse_sb_defaults(sb);
if (ctx->is_bdev) {
#ifdef CONFIG_BLOCK
err = -EINVAL;
if (!sb_set_blocksize(sb, ctx->blksize))
goto err;
#endif
} else {
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
}
sb->s_subtype = ctx->subtype;
ctx->subtype = NULL;
if (IS_ENABLED(CONFIG_FUSE_DAX)) {
err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
if (err)
goto err;
}
if (ctx->fudptr) {
err = -ENOMEM;
fud = fuse_dev_alloc_install(fc);
if (!fud)
goto err_free_dax;
}
fc->dev = sb->s_dev;
fm->sb = sb;
err = fuse_bdi_init(fc, sb);
if (err)
goto err_dev_free;
/* Handle umasking inside the fuse code */
if (sb->s_flags & SB_POSIXACL)
fc->dont_mask = 1;
sb->s_flags |= SB_POSIXACL;
fc->default_permissions = ctx->default_permissions;
fc->allow_other = ctx->allow_other;
fc->user_id = ctx->user_id;
fc->group_id = ctx->group_id;
fc->legacy_opts_show = ctx->legacy_opts_show;
fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
fc->destroy = ctx->destroy;
fc->no_control = ctx->no_control;
fc->no_force_umount = ctx->no_force_umount;
err = -ENOMEM;
root = fuse_get_root_inode(sb, ctx->rootmode);
sb->s_d_op = &fuse_root_dentry_operations;
root_dentry = d_make_root(root);
if (!root_dentry)
goto err_dev_free;
/* Root dentry doesn't have .d_revalidate */
sb->s_d_op = &fuse_dentry_operations;
mutex_lock(&fuse_mutex);
err = -EINVAL;
if (ctx->fudptr && *ctx->fudptr)
goto err_unlock;
err = fuse_ctl_add_conn(fc);
if (err)
goto err_unlock;
list_add_tail(&fc->entry, &fuse_conn_list);
sb->s_root = root_dentry;
if (ctx->fudptr)
*ctx->fudptr = fud;
mutex_unlock(&fuse_mutex);
return 0;
err_unlock:
mutex_unlock(&fuse_mutex);
dput(root_dentry);
err_dev_free:
if (fud)
fuse_dev_free(fud);
err_free_dax:
if (IS_ENABLED(CONFIG_FUSE_DAX))
fuse_dax_conn_free(fc);
err:
return err;
}
EXPORT_SYMBOL_GPL(fuse_fill_super_common);
static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
{
struct fuse_fs_context *ctx = fsc->fs_private;
struct file *file;
int err;
struct fuse_conn *fc;
struct fuse_mount *fm;
err = -EINVAL;
file = fget(ctx->fd);
if (!file)
goto err;
/*
* Require mount to happen from the same user namespace which
* opened /dev/fuse to prevent potential attacks.
*/
if ((file->f_op != &fuse_dev_operations) ||
(file->f_cred->user_ns != sb->s_user_ns))
goto err_fput;
ctx->fudptr = &file->private_data;
fc = kmalloc(sizeof(*fc), GFP_KERNEL);
err = -ENOMEM;
if (!fc)
goto err_fput;
fm = kzalloc(sizeof(*fm), GFP_KERNEL);
if (!fm) {
kfree(fc);
goto err_fput;
}
fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
fc->release = fuse_free_conn;
sb->s_fs_info = fm;
err = fuse_fill_super_common(sb, ctx);
if (err)
goto err_put_conn;
/*
* atomic_dec_and_test() in fput() provides the necessary
* memory barrier for file->private_data to be visible on all
* CPUs after this
*/
fput(file);
fuse_send_init(get_fuse_mount_super(sb));
return 0;
err_put_conn:
fuse_conn_put(fc);
kfree(fm);
sb->s_fs_info = NULL;
err_fput:
fput(file);
err:
return err;
}
static int fuse_get_tree(struct fs_context *fc)
{
struct fuse_fs_context *ctx = fc->fs_private;
if (!ctx->fd_present || !ctx->rootmode_present ||
!ctx->user_id_present || !ctx->group_id_present)
return -EINVAL;
#ifdef CONFIG_BLOCK
if (ctx->is_bdev)
return get_tree_bdev(fc, fuse_fill_super);
#endif
return get_tree_nodev(fc, fuse_fill_super);
}
static const struct fs_context_operations fuse_context_ops = {
.free = fuse_free_fc,
.parse_param = fuse_parse_param,
.reconfigure = fuse_reconfigure,
.get_tree = fuse_get_tree,
};
/*
* Set up the filesystem mount context.
*/
static int fuse_init_fs_context(struct fs_context *fc)
{
struct fuse_fs_context *ctx;
ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->max_read = ~0;
ctx->blksize = FUSE_DEFAULT_BLKSIZE;
ctx->legacy_opts_show = true;
#ifdef CONFIG_BLOCK
if (fc->fs_type == &fuseblk_fs_type) {
ctx->is_bdev = true;
ctx->destroy = true;
}
#endif
fc->fs_private = ctx;
fc->ops = &fuse_context_ops;
return 0;
}
bool fuse_mount_remove(struct fuse_mount *fm)
{
struct fuse_conn *fc = fm->fc;
bool last = false;
down_write(&fc->killsb);
list_del_init(&fm->fc_entry);
if (list_empty(&fc->mounts))
last = true;
up_write(&fc->killsb);
return last;
}
EXPORT_SYMBOL_GPL(fuse_mount_remove);
void fuse_conn_destroy(struct fuse_mount *fm)
{
struct fuse_conn *fc = fm->fc;
if (fc->destroy)
fuse_send_destroy(fm);
fuse_abort_conn(fc);
fuse_wait_aborted(fc);
if (!list_empty(&fc->entry)) {
mutex_lock(&fuse_mutex);
list_del(&fc->entry);
fuse_ctl_remove_conn(fc);
mutex_unlock(&fuse_mutex);
}
}
EXPORT_SYMBOL_GPL(fuse_conn_destroy);
static void fuse_sb_destroy(struct super_block *sb)
{
struct fuse_mount *fm = get_fuse_mount_super(sb);
bool last;
if (fm) {
last = fuse_mount_remove(fm);
if (last)
fuse_conn_destroy(fm);
}
}
static void fuse_kill_sb_anon(struct super_block *sb)
{
fuse_sb_destroy(sb);
kill_anon_super(sb);
}
static struct file_system_type fuse_fs_type = {
.owner = THIS_MODULE,
.name = "fuse",
.fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
.init_fs_context = fuse_init_fs_context,
.parameters = fuse_fs_parameters,
.kill_sb = fuse_kill_sb_anon,
};
MODULE_ALIAS_FS("fuse");
#ifdef CONFIG_BLOCK
static void fuse_kill_sb_blk(struct super_block *sb)
{
fuse_sb_destroy(sb);
kill_block_super(sb);
}
static struct file_system_type fuseblk_fs_type = {
.owner = THIS_MODULE,
.name = "fuseblk",
.init_fs_context = fuse_init_fs_context,
.parameters = fuse_fs_parameters,
.kill_sb = fuse_kill_sb_blk,
.fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};
MODULE_ALIAS_FS("fuseblk");
static inline int register_fuseblk(void)
{
return register_filesystem(&fuseblk_fs_type);
}
static inline void unregister_fuseblk(void)
{
unregister_filesystem(&fuseblk_fs_type);
}
#else
static inline int register_fuseblk(void)
{
return 0;
}
static inline void unregister_fuseblk(void)
{
}
#endif
static void fuse_inode_init_once(void *foo)
{
struct inode *inode = foo;
inode_init_once(inode);
}
static int __init fuse_fs_init(void)
{
int err;
fuse_inode_cachep = kmem_cache_create("fuse_inode",
sizeof(struct fuse_inode), 0,
SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
fuse_inode_init_once);
err = -ENOMEM;
if (!fuse_inode_cachep)
goto out;
err = register_fuseblk();
if (err)
goto out2;
err = register_filesystem(&fuse_fs_type);
if (err)
goto out3;
return 0;
out3:
unregister_fuseblk();
out2:
kmem_cache_destroy(fuse_inode_cachep);
out:
return err;
}
static void fuse_fs_cleanup(void)
{
unregister_filesystem(&fuse_fs_type);
unregister_fuseblk();
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(fuse_inode_cachep);
}
static struct kobject *fuse_kobj;
static int fuse_sysfs_init(void)
{
int err;
fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
if (!fuse_kobj) {
err = -ENOMEM;
goto out_err;
}
err = sysfs_create_mount_point(fuse_kobj, "connections");
if (err)
goto out_fuse_unregister;
return 0;
out_fuse_unregister:
kobject_put(fuse_kobj);
out_err:
return err;
}
static void fuse_sysfs_cleanup(void)
{
sysfs_remove_mount_point(fuse_kobj, "connections");
kobject_put(fuse_kobj);
}
static int __init fuse_init(void)
{
int res;
pr_info("init (API version %i.%i)\n",
FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
INIT_LIST_HEAD(&fuse_conn_list);
res = fuse_fs_init();
if (res)
goto err;
res = fuse_dev_init();
if (res)
goto err_fs_cleanup;
res = fuse_sysfs_init();
if (res)
goto err_dev_cleanup;
res = fuse_ctl_init();
if (res)
goto err_sysfs_cleanup;
sanitize_global_limit(&max_user_bgreq);
sanitize_global_limit(&max_user_congthresh);
return 0;
err_sysfs_cleanup:
fuse_sysfs_cleanup();
err_dev_cleanup:
fuse_dev_cleanup();
err_fs_cleanup:
fuse_fs_cleanup();
err:
return res;
}
static void __exit fuse_exit(void)
{
pr_debug("exit\n");
fuse_ctl_cleanup();
fuse_sysfs_cleanup();
fuse_fs_cleanup();
fuse_dev_cleanup();
}
module_init(fuse_init);
module_exit(fuse_exit);